<HTML dir=ltr><HEAD>
<META content="text/html; charset=unicode" http-equiv=Content-Type>
<META name=GENERATOR content="MSHTML 8.00.6001.18904"></HEAD>
<BODY>
<DIV dir=ltr id=idOWAReplyText16695>
<DIV dir=ltr><FONT color=#000000 size=2 face=Arial>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: black; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'">Hello Mohannad,</SPAN><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"> <o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'">Just to make sure, you didn’t mean the <STRONG>latitude</STRONG> is MINUS 24.65 (so on the southern hemisphere, in which case the sun will come from the north)?</SPAN><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'">Otherwise, your latitude is around the latitude of the tropic of cancer. This is a special location and what I would do is plot the solar radiation per m2 per orientation just to check if then you understand. You can also leave out the solar radiation first, to check if this is really the cause. </SPAN><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"> <o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><STRONG><SPAN style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'">Qvent is defined as (see manual): QVENT sensible ventilation energy <U>gain</U> of zone</SPAN><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><o:p></o:p></SPAN></STRONG></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'">So that negative values are given if there are ventilation outputs, i.e. LOSSES. This should only occur of your ventilation air is a lower temperature than you indoor air.</SPAN><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"> <o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><STRONG><SPAN style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'">Qcool is defined as: QCOOL sensible <U>cooling</U> demand of zone (<U>positive values) </U></SPAN><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><o:p></o:p></SPAN></STRONG></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'">This means POSITIVE values are given for energy outputs (so this is an opposite definition of Qvent) </SPAN><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'">Qcool can be positive while Qvent is negative, when solar or internal gains are bigger than the total losses and thus additional cooling is required.</SPAN><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"> <o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'">Qcool refers to the cooling demand of your zone that is needed according to the energy balance of your zone (and your setpoints). If you use external air at external air temperature (and no other cooling items, such as a cooling floor), <SPAN style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'">Qcool is your total cooling demand. </SPAN></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'"><SPAN style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'">H</SPAN>owever, if you use ventilation air at a temperature different from Toutside, this means additional cooling is required to produce the air at this temperature. I think in that case you need to calculate the energy required for cooling down the air (from Toutside to Tair-inlet) in order to come to the total cooling demand. Qvent is in this case not related to the cooling demand, only to the energy balance of the zone.</SPAN><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"> <o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'">I hope this is of any help.</SPAN><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"> <o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'">Kind regards, Sabine Jansen</SPAN><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"> <o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'">p.s. The energy balance of the zone is given in balance output 4, but in the manual there is one small error in the definition of Qtrans, which should be defined in the opposite way, that is, it is also included as a GAIN in the balance equation, meaning positive values are gains to the zone and negative values are losses.</SPAN><SPAN style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 12pt; mso-fareast-font-family: 'Times New Roman'"><o:p></o:p></SPAN></P>
<P style="MARGIN: 0cm 0cm 10pt" class=MsoNormal><o:p><FONT size=3 face=Calibri> </FONT></o:p></P></FONT></DIV></DIV>
<DIV dir=ltr><BR></DIV>
<DIV dir=ltr>
<HR tabIndex=-1>
</DIV>
<DIV dir=ltr><FONT size=2 face=Tahoma><B>Van:</B> Mohannad Bayoumi [mailto:mohannad.b@gmail.com]<BR><B>Verzonden:</B> do 1-4-2010 23:46<BR><B>Aan:</B> trnsys-users@cae.wisc.edu<BR><B>Onderwerp:</B> [TRNSYS-users] Higher cooling demand in the north zone! - QVENT andQCOOL<BR></FONT><BR></DIV>
<DIV>Hello,
<DIV><BR></DIV>
<DIV>I am simulating the energy demand for a floor in an office building - Lat 24.65°. </DIV>
<DIV><BR></DIV>
<DIV>The floor has 4 main zones facing the 4 different orientations.</DIV>
<DIV><BR></DIV>
<DIV>U-Outwall: 0.15 Wh/m2.K</DIV>
<DIV>U-Glass: 0.5 Wh/m2.K</DIV>
<DIV>
<DIV>G-Glass: 56 %</DIV>
<DIV>External shading factor: 88%</DIV>
<DIV><BR></DIV>
<DIV>I keep getting a higher cooling demand (QCOOL) for the northern zone against the eastern and the western ones. I tried many times with and without inner loads and shading devices. I also tried with mechanical ventilation - 18°C temperature of supplied air and 0.2 h^-1 Leaking.</DIV>
<DIV><BR></DIV>
<DIV>1- What can be the reason for these surprising results?</DIV>
<DIV><BR></DIV>
<DIV>I still can not understand why the QVENT values are in negative while the QCOOL are in positive, although the cooling process is to lead the heat away from the body or the space. </DIV>
<DIV>2- If I would like to find out the total cooling demand of a zone, should I use the QCOOL or QVENT values, or should I add them together?? </DIV></DIV>
<DIV><BR></DIV>
<DIV>Thank you</DIV>
<DIV><BR></DIV>
<DIV>Mohannad Bayoumi</DIV></DIV></BODY></HTML>